Glasgow Zoo Park
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Greater Rhea , Rhea americana
Habitat: low-lying grasslands

Status: Common

Located: North Eastern Brazil to Central Argentina.

Size: 5 feet tall

Incubation: 35 - 40 days

No. of Young: Up to 18 eggs

Lifespan: 15 - 20 years

Breeding: 5 to 7 hens to a cock. The male prepares the nest. Females lay up to 18 eggs which the cock incubates and thereafter rears the young on his own.

Food in wild: Adult - mainly grass, some insects and small invertebrates. Young - only insects.

Food in zoo: Mazuri pellets, flaked maize, apples, brown bread, lettuce, turkey rearer pellets.

Rhea (male): at nest scrape ,

© Andy Smyth, Glasgow

Rhea (male): at nest scrape

The seven female and two male rheas have produced numerous eggs, and both males - as is usual in ratites - have ‘gone broody’. We pondered whether or not to remove some of the eggs, and with hindsight perhaps we should have done. The two males have been trying to incubate forty or fifty eggs. They have a nest in the middle of the paddock amongst the long grass.

The problem is that, with so many eggs, they are unable to cover them all at one time. In consequence, eggs get chilled. During incubation, these get rolled back into the nest and some other egg in turn gets chilled. By the end of a lengthy incubation period most of the clutch may have perished in this way - a recognised phenomenon amongst poultry and waterfowl breeders. We weren’t desperate to breed numerous rheas this year anyway, but regret not restricting the numbers of eggs these males were attempting to cover.

 Rheas are the true inhabitants of the South American grasslands or pampas. Examples of pampas grass can be seen on the lawn, halfway up the main drive just down from the Barbary sheep. Imported into Britain on many occasions by landowners and collectors like the Duke of Bedford for his Woburn estate, rheas were first bred in Scotland during the nineteenth century. They are now considered almost - though not quite - domesticated, with a white variation being quite common.
 Distribution in the wild is from north-eastern Brazil to central Argentina. Although conspicuous to our eyes, on the pampas, crouched, immobile, amongst the tussocky grass, they are almost invisible. Then, when something alarms them, off they go, in typical, high-stepping ostrich style, reaching speeds of 30 m.p.h., and zig-zagging this way and that, often with wings outstretched and bending to one side, then the other, at acute angles.
 Their lifespan is 15-20 years, and we have always found them trouble-free and very hardy, seemingly impervious to the coldest temperatures. Our group of two males and five females are descended from birds we first bred back in 1980 (at the bottom of the hill where the llamas are now kept). They are four years old. Each female lays from 15-20 eggs - one every second day - in May and June. These are gathered together by the cock birds and incubated for about 35 days. In 1999 we made the mistake of not limiting the numbers of eggs each male attempted to 'cover' so, one by one, each rolled out of the nest for a period and was chilled. This year we intend to artificially incubate some, letting the fathers incubate smaller clutches of 15-18 eggs. Some of last year's eggs have been left our for you to look at.
 Chicks when they hatch are insectivorous, before moving on to short grass, shoots and invertebrates of all sorts. The father carries out all the incubation and rearing. 'Surplus' eggs can be artificially incubated, but great care has to be taken with the chicks, as sometimes leg problems can result if the diet is not precisely correct. Adults in the wild feed on all sorts of vegetation supplemented whenever possible with all sorts of small creatures. Male birds have darker, blacker necks and are a little taller. One of the female birds appears paler than the others, and we suspect this is some form of dilute such as a 'Silver' or a 'Cinnamon' variant in other bird species.